Refer to the thread in my signature. We need to know the purpose.
For $6 more, you can get better Ripjaws (1333 mhz, CAS Latency 7).
For $155 (only $15 more), you can get the much more future proof, much better ATI HD 5770.
I wouldn't trust that Rosewill PSU. Stick to Corsair, Antec Earthwatts or OCZ (OCZ's 700W StealthXStream is $50 right now).
I also don't particularly care for the NZXT cases. Generally, they're not very high quality, and the "special" features they included typically don't work. I especially don't like that one when the HAF 922 is the same price.
I would switch that Seagate HDD for a 1 TB Samsung Spinpoint F3. It's cheaper and faster.
You want the F3. The F3 is the newest drive, and uses 500 GB platters. The only drives that use these are the F3 (500 GB, $55 and 1 TB, $85), Seagate 7200.12 (500 GB, $55 and 1 TB, $85) and Western Digital 2 TB (probably $300).
So the only suitable replacement for the F3 is the Seagate 7200.12. And that should only be done if the F3 is sold out, and you can't wait to buy it.